EX native 25p -> 25PsF/50i at DVinfo.net

Piotr Wozniacki · February 4th, 2010, 01:37 AM

Dan at al,

I came across this statement of a (known as knowledgeable) person on another forum:

"I'm concerned about loss of chroma resolution, because when I convert a 30p stream to 60i, the colors turn all blocky and it looks just as bad as HDV. I'm really disappointed that the SDI output is not truly progressive. All the PsF hocus pocus leaves too much room for destruction of the chroma information in the process."

Is he right that in the process of recording my EX1's "native" 25p as 25PsF in the interlaced 50i stream, some 4:2:2 color advantages are being lost?

Please tell me it's not true ;)

Rafael Amador · February 4th, 2010, 05:28 AM

For me that no make sense.
When you read a Progressive 422 Uncompress file as Interlaced, the only thing you do is to alter the order of the lines on reading.
Lines are composed of longitudinal blocks of 4 pixels, and are independent from each other so you can read them in the order you want.

If would be talking about 420 stuff, this would be different. Blocks are composed of 2x2 pixels in alternate lines: Two pixels from an even line, and two pixels from the odd line that is underneath. This makes the compression pattern different in Let say that the lines are not independent and you can not read the picture without rebuilding all the blocks pattern.
This would degrade the picture.
Rafael

Piotr Wozniacki · February 5th, 2010, 12:13 AM

Thanks Rafael - this sounds convincing.

Any other take?

Dan Keaton · February 5th, 2010, 02:15 AM

Dear Piotr,

I do not know the context in which the statement was made.

However, this statement does not apply to the nanoFlash.

We handle PSF properly without loss of image quality, provided one sets the Record PSF>Prog(ressive) setting properly.

For 23.976, 23.98, 24p, we set this flag automaticaly, internally, for the user.

For 25p, 29.97p, and 30p, you must set the flag, since you are sending the nanoFlash progressive images.

For 50i, 59.94i, and 60i, you must set the flag off, since you are sending interlaced images.

Piotr Wozniacki · February 5th, 2010, 09:38 AM

Thanks Dan for you positive answer.

February 4th, 2010, 01:37 AM	#1
Piotr Wozniacki Inner Circle Join Date: Aug 2006 Location: Poland Posts: 4,086	EX native 25p -> 25PsF/50i Dan at al, I came across this statement of a (known as knowledgeable) person on another forum: "I'm concerned about loss of chroma resolution, because when I convert a 30p stream to 60i, the colors turn all blocky and it looks just as bad as HDV. I'm really disappointed that the SDI output is not truly progressive. All the PsF hocus pocus leaves too much room for destruction of the chroma information in the process." Is he right that in the process of recording my EX1's "native" 25p as 25PsF in the interlaced 50i stream, some 4:2:2 color advantages are being lost? Please tell me it's not true ;) __________________ Sony PXW-FS7 \| DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive Last edited by Piotr Wozniacki; February 4th, 2010 at 03:16 AM.

February 5th, 2010, 12:13 AM	#3
Piotr Wozniacki Inner Circle Join Date: Aug 2006 Location: Poland Posts: 4,086	Thanks Rafael - this sounds convincing. Any other take? __________________ Sony PXW-FS7 \| DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

February 5th, 2010, 02:15 AM	#4
Dan Keaton Inner Circle Join Date: Dec 2002 Location: Augusta Georgia Posts: 5,421	Dear Piotr, I do not know the context in which the statement was made. However, this statement does not apply to the nanoFlash. We handle PSF properly without loss of image quality, provided one sets the Record PSF>Prog(ressive) setting properly. For 23.976, 23.98, 24p, we set this flag automaticaly, internally, for the user. For 25p, 29.97p, and 30p, you must set the flag, since you are sending the nanoFlash progressive images. For 50i, 59.94i, and 60i, you must set the flag off, since you are sending interlaced images. __________________ Dan Keaton Augusta Georgia

February 5th, 2010, 09:38 AM	#5
Piotr Wozniacki Inner Circle Join Date: Aug 2006 Location: Poland Posts: 4,086	Thanks Dan for you positive answer. __________________ Sony PXW-FS7 \| DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

February 4th, 2010, 05:28 AM	#2
Rafael Amador Major Player Join Date: Jun 2009 Location: Vientiane (Lao PDR) Posts: 349	For me that no make sense. When you read a Progressive 422 Uncompress file as Interlaced, the only thing you do is to alter the order of the lines on reading. Lines are composed of longitudinal blocks of 4 pixels, and are independent from each other so you can read them in the order you want. If would be talking about 420 stuff, this would be different. Blocks are composed of 2x2 pixels in alternate lines: Two pixels from an even line, and two pixels from the odd line that is underneath. This makes the compression pattern different in Let say that the lines are not independent and you can not read the picture without rebuilding all the blocks pattern. This would degrade the picture. Rafael